Process of discharging with hydrosulfite paste.



UNITED STATES Patented November 17, 1903;

PATENT OFFICE.

LEOPOLD HEINRI CH DEHOFF, OF LUDWIGSHAFEN-ON-Tl-IE-RHINE, GER- MANY, ASSIGNOR TO THE BADISOHE ANILIN &; SODA FABRIK, OF LUD- WIGSHAFENON-THE-RHINE, BAVARIA, GERMANY, CORPORATION.

OF BADEN.

PROCESS OF DISCHARGING WITH HYDROSULFITE PASTE.

SPECIFICATION forming part of Letters Patent No. 744,501, dated November 17, 1903. Application filed August 18,1900. Serial lilo. 27.814. (N0 specimens.)

To all whom it may concern.-

Beitknown that I, LEOPOLD HEINRICH DE- HOFF, doctor of philosophy and chemist, a

subject of the King of Saxony, residing at Ludwigshafen-on-the-Rhine, in the Kingdom of Bavaria and Empire of Germany, haveinvented new Processes of Discharging. with Hydrosulfite Paste, of which the following is a specification.

I This invention relates to a new discharging agent and also to the usethereof in an improvement in the art of discharging dyed material by means of salts of hydrosulfurous acid, such as sodium hydrosulfite, sodiumzinc hydrosulfite, &c. V

In the prior art the hydrosulfite employed was generated at or practically at the time and place of employment and was then always accompanied by an excess of themetallic zinc used. It was this excess of zinc which caused the disadvantages and drawbacks, in the application of hydrosulfites in discharging operations. These drawbacks and disadvantages were that if the dischargepaste was too thick the excess of zinc-dust which was necessarily present soon clogged up the design on the rollers. If the paste was too thin, the zinc-dust settled to the bottom of the box and was not available for discharging purposes on the material to be discharged.

, Now this improvement in the art of discharging dyed goods by means of sodium or another hydrosulfite and according to which improvement the presence of metallic zinc or other free or uncombined metal is com pletely avoided is based upon the discovery that such concentrated solutions of the alkali hydrosulfites as can be obtained when working according to the process which is described in German Patent No. 112,483 for the production of the solution of hydrosulfites, or the new solid sodium hydrosulfitewhose preparation is likewise described in said German Patent No. 112,483, dated May24, 1899, and issued August 1, 1900, or the zinc-sodium hydrosulfite which is the subject of United States Patent No. 662,339, of'November 20, 1900, or the zinc-calcium hydrosulfite which is the subject ofUnite'd States Patent No. 662,338, of November 20, 1900, are capable of use in a discharge paste as are other discharging agents. Since discharge-pastes so prepared are free from metallic zinc, the above-mentioned drawbacks and disadvantages do not exist when such pastes are employed for discharging purposes. Hitherto no solution of a hydrosulfite carrying no metallic zinc or a solid product containing a,

five hundred and eighty (580) grams of gum water (1:1) as ,far as is possible, and the whole is diluted to a volume of one liter by means of water. This paste is printed onto the dyed goods to be discharged. The soprepared material is then dried and steamed. If nitrosamine red is to be discharged, the steaming is best done in a Mather-Plait and lasts for about five (5) or ten (10) minutes. Other dyestutf-disch'arges on silk'or cotton are steamed for about one hour without pressure. For woolen material the steam employed should be as moist as possible.

Example 2- Variegatecl. discharge-Bottom: Acid violet 6 B N. Discharge-paste:'

Thirty grams rheonin are dissolved in sixty cubic centimeters of water, one hundred grams acetin J, and five hundred and sixty grams gum-water by the aid of heat. After the paste has cooled add two hundred and fifty grams of zinc-sodium hydrosulfite and stir until solution has ceased. Print, dry, and steam.

Hereinafter I employ the word metal as meaning metal in the free or uncombined state.

What is claimed is 1. The process of discharging dyed material by means of a hydrosnlfite which consists in mixing togethera hydrosulfite which is free from metal and a thickening mixture, printing the result onto the material to be discharged, then drying and steaming the same.

2. The process of discharging dyed material by means of a hydrosulfite which consists in mixing together zinc-sodium hydrosullite which is free from metal and a thickening mixture, printing the result onto the material to be discharged, then drying and steaming the same. v V

3. The process of discharging dyed material by means of a hydrosulfite which consists in printing onto the material to be discharged a mixture which is free from metal and contains a hydrosulfite, a thickening agent and a dyestufi, then drying and steaming the same.

4. The process of discharging dyed material by means of a hydrosulfite which consists in printing onto the material to be discharged a mixture which is free from metal and contains zinc-sodium hydrosulfito, a thickening agent and a dyestulf, then drying and steaming the same.

5. The improvement in the art of discharging dyed material by means of a hydrosulfite which consists in printing onto the material to be discharged a mixture which is free from metal and contains a hydrosulfite and a thickening agent.

6. The improvement in the art of discharging dyed material by means of a hydrosulfite which consists imprinting onto the material to be discharged a mixture which is free from metal and contains zinc-sodium hydrosulfite and a thickening agent.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

LEOPOLD HEINRICH DEHOFF.

Witnesses:

BERNHARD C. HESSE, PAUL JULIUS. 

